Conventionally, for an image processing device of this type, one mainly comprising a photosensitive element array wherein a plurality of photosensitive elements are provided in a line; thin film transistors, the number of which corresponds to that of the photosensitive elements and which are connected in series with the photosensitive elements; and a drive circuit to control these thin film transistors is known as described in Japanese unexamined patent application number Hei 2-265362 (1990). In such an image processing device, the photosensitive elements are divided into blocks of elements, the output of the thin film transistors connected to the photosensitive elements disposed in the same positions in each block are connected together, and the gate electrodes of the thin film transistors connected to the photosensitive elements in each block are also connected together. Reading of image signals is carried out block by block, and moreover, as the thin film transistors connected to the photosensitive elements disposed in the same block are conductive simultaneously, the photosensitive elements in each block output signals simultaneously.
In the above described conventional device, however, as the signal lines connected to the output lines of switching transistors are disposed in a matrix formation and the switching transistors disposed in the same block are conductive simultaneously, signal crosstalk occurs among the intersecting signal lines, which makes it difficult to read image signals precisely. To solve one defect of the above-identified conventional device, an image processing device as shown in FIG. 9 has previously been developed.
As shown in FIG. 9, the image processing device comprises a photosensitive element array 21 wherein a plurality of photosensitive elements 20 are provided; thin film transistors 22 connected to the corresponding photosensitive elements 20 and the number of which is the same as that of the photosensitive elements; a gate driver 23 to control the thin film transistors 22; an analog multiplexer 24 to output in turn the image signals coming from the photosensitive elements 20 through the thin film transistors 22. Here, the photosensitive elements 20 are divided into blocks of elements, and the output of the thin film transistors 22 connected to the photosensitive elements 20 disposed in the same block are connected together and are connected to the input of the analog multiplexer 24. Further, if the photosensitive elements 20 of each block are numbered from the left side as shown in FIG. 9, the gate electrodes of the thin film transistors 22 connected to the corresponding photosensitive elements 20 disposed in the same positions in each block, for example P.sub.11, P.sub.21 and P.sub.M1, are connected together and are connected to the gate driver 23. Therefore, data lines 25, the number of which corresponds to the number of blocks, are connected to the analog multiplexer 24 and gate lines 26, the number of which corresponds to the number of photosensitive elements in a block are connected to the gate driver 23. In this image processing device, reading of image signals is carried out as follows. A Gate drive pulse signal having a predetermined pulse width is outputted from the gate driver 23 as shown in FIG. 10, by which image signals from the photosensitive elements 20 disposed in the same positions in each block are inputted to the analog multiplexer 24 through the thin film transistors 22 which are conductive. The analog multiplexer 24 outputs in turn, as shown in FIG. 10, the image signals inputted from each block in accordance with the scan clock pulses generated internally, so the image signals are outputted not in sequential order along the scan line, but with the first element of the first block P.sub.11 followed by the first element of the second block P.sub.21, then the first element of the third block P.sub.31, and so on (in FIG. 9, image signals are outputted with an interval N between successive pixels). Therefore, this image processing device is different from the conventional one in this point, that is, the data lines 25 do not cross one another and signal crosstalk does not occur, by which precise image signals can be obtained.
This device, however, has a problem, in that, as the image signals are outputted not in the spatial order of the photosensitive elements, the image signals read from the analog multiplexer must be rearranged in the spatial order of the photosensitive elements when the image signals read are displayed in a display device or printed by a printing device.